.heat-cell {
  transition: background-color 0.2s ease, color 0.2s ease;
  padding: 0.25rem 0.5rem;
}
.heat-legend {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  margin-bottom: 0.5rem;
}
.heat-legend .swatch {
  width: 1.5rem;
  height: 1rem;
  border: 1px solid rgba(0,0,0,0.1);
}